What would you do if your child stopped attending school lessons?

Roo🌸
As important as education is, I know kids, despite getting detentions, still truant. And I'm aware some parents accept it and let them come home instead of going to certain lessons. I even see some kids in uniform outside school premises smoking and messing about during school hours. Where do you stand? Even if you don't have kids, what would you do if in that situation? Do you think schools should do more to prevent truanting or is it up to the parents to fix it?